Locking means for hydraulic brake systems



Jan. 7, 1941. E, MARTNSON 2,227,661

LOCKING MEANS FOR HYDRAULICA BRAKE SYSTEMS Filed June 1. 1939 Patented Jan. 7,l 12941 [UNITED STATES PATENT OFFICE Edwin Martinson, Holdrege, N ebr. Application June 1, 1939, Serial No'. 276,921

' 1 Claim (Cl. 18S-152) This invention relates generally to the class oi fluid or hydraulic braking systems ior wheeled vehicles and pertains particularly to improved means for locking such systems.

Ii I' The primary object of the present invention is to provide ina -iluid or hydraulic braking system, a novel means whereby the system may be lock or the iluid held against movement therein after the brakes have been set so that the operator of the vehicle may remove his foot irom the ioot pedal without tear of the brakes releasing and the vehicle moving.

The present device is of particular benet in hydraulic brake systems where it is necessary to l5, set the brakes when the 'vehicle is stopped on a grade or when it 1s necessary to jack up a wheel ot the vehicle. particularly where the vehicle is on a grade, and the device also may be employed in place oi the regular emergency or hand set brake which at the present time forms a standard part oi vehicle braking systems.

Another object of the invention is to provide in a system of the character described, a iluid how controlling valve voi noveldesign wherein 2d the seepage oi iluid through the valve when the latter is closed, is positively prevented.

The invention will be best understood from a consideration oi the :following detailed description taken in connection with the accompanying drawing forming part oi this specification, with the understanding, however, that the invention is not to be con to any strict conformity with the showing of the drawing but may be changed or modined so long as such changes or modifica- 35' tions mark no material departure from the salient features of the invention as expressed in the appended claim.

In the drawing: I v Fig. 1 is a diagram ofl a uid brake system w showing the device embodying the present invention connected therein.

Fig. 2 is a longitudinal sectional veW of the locking valve.

Referring now more particularly to the draw- 45 ing. Fig. l represents a conventional fluid braking systernin which the front wheel brakes are indicated by4 the numeral I and the rear wheelbrakeo are indicated by the numeral 2.

'I'he numeral I designates the master fluid cyl- 50 inder which is controlled by the usual foot pedal y 4 and which has leading therefrom the iiuid line l.

A iiuid line 6 leads to the iront brake actuating units I while a similar line 8 leads to the rear ll brake actuating units 9, and between these lines 6 and 8 andy the iluid line 5, is interposed the locking or control valve embodying the present invention, the same being generally indicated bythe numeral III.

l In accordance with the present invention, the 5 control or locking valve I0 comprises an elongated cylindrical casing II which at one end is provided with a packed head I2 through which a piston stem I3 rises, the outer end oi the stem having the head I4 thereon. vThis valve casing II 10 is adapted to be mounted in any suitable manner on the vehicle instrument board I5 so that the piston actuating stem I3 and head I4 are accessible to the driver of the vehicle.

The casing II is provided with the two bushed l5 inlet ports I6 and I'I which are connected with the master fluid line 5 leading from the cylinder 3 in the manner shown ln Fig. l. At its inner end each of these ports I6 and Il is formed to provide a. ball valve seat I8. 2o

Opposite theports I6 and I1 are the bushed outlet ports I9 and 20, one of which is connected with the fluid line I8 while the other one is connected with the fluid line 6. y

Slidably disposed within thevcylinder II is a relatively long piston body 2I which has formed transversely therethrough the cross passages 22 and 723 which are designed respectively to establlsh communication betweenV the ports IS--IS and the ports Il-20, when the piston has beenv shifted in the proper direction and to the proper extent in the cylinder.

.At one side of each transverse passage there is formed in the piston body a recess 24 in which is aspring 26 and a valve ball 26. The ball is 35 constantly urged outwardly by the spring 25 and under normal operating conditions tor the brake system it engages against the inner surface of the cylinder wall at one sldeof an inlet port but when the valve is to be closed to lock-the system, the valve ball'26 will be shifted into a seat I8 of an inlet port.

Adjacent -each end of the piston 2| is a packing 21 which, oi course. is provided to prevent fluid leakage past the ends of the piston and into the ends of the cylinder.

In order that the piston body 2l may be moved freely backwardly and forwardly in the cylinder, air vents 28 are provided in the cylinder wall adjacent the ends of the cylinder.

In vthe operation of a hydraulic brake system equipped with a locking valve oi the character here described, the piston body 2I will ,be normally in a position where the cross passages 22 will establish the necessary communication be- 55 block the return of uid through the lines 8 and 8 to the master cylinder when the foot pedal t has been released. Thus it will be seen that' the vehicle may be lett with the full assurance that the brakes will be securely applied so that even though the vehicle may he on a grade, it will not shift from its position.

What is claimed is: l

In a hydraulic brake system locking means for a motor vehicle having a dash and vfront and rear pairs of brake operating uid actuated pistons and a foot lever controlled master uld cylinder. a single pipe line leading from said master cylinder,-a pair of pipe lines coupled with and leading fromsaid single line. one oi the` pipe lines of A 2,237,661 tween the oppositely disposed inlet and (muet,

said pair being connected by a pair oi branch pipes with, cylinders for the iront brake operating pistons. the other pipe line ot said pair being connected through two branch lines with the cylinders for the rear brake operating pistons, and a hand controlled valve for said pair of pipe lines mounted on said dash, comprising a shell having two inlet ports and twooutlet ports, the shell being connected across and interposed in the pair of pipe lines and having each inlet port connected with one side of one of the pair of pipe lines and having each outlet port connected with the other side ci one of the pair of pipe lines, and a reciprocable plug in said shell having a pair of passages formedtransverselytherethroughandarranged to simultaneouslyestablish communication between the pairs of inlet and outlet ports when the plug is in one position and to shut oi! communication between the pairs of inlet and outlet ports when the plug is in another position, said plug operating entirely independently o! the master cylinder operating means and when in shut-oil position, holding said brake actuating pistons in brake applied position when the master cylinder controlling lever is released EDWIN MARTINSON. 

